1. Field of the Invention
The present invention relates to a portable terminal. More particularly, the present invention relates to a linear vibration generating apparatus employed as a non-acoustic signal receiving apparatus.
2. Description of the Related Art
A linear vibration generating apparatus used for a non-acoustic signal receiving apparatus of a portable terminal has quick vibration characteristics compared to an existing eccentric rotary vibration motor due to its short motion stroke and a resilient force of a resilient body.
Such a linear vibration generating apparatus generally includes a vibrator having a permanent magnet and a stator for supporting the vibrator, in which case the permanent magnet is moved upward and downward due to a mutual interaction between an electromagnetic force generated when a current is applied to a coil disposed in the stator and a magnetic force generated in the permanent magnet, generating vibrations.
FIG. 1 is a sectional view illustrating a linear vibration generating apparatus according to the related art.
Referring to FIG. 1, an existing linear vibration generating apparatus 10 includes a vibrator 14 and a stator 11. The vibrator 14 includes a yoke 141 having a burring part 18, a permanent magnet 15, and a weight body 16, and the stator 11 includes an outer case 12, a bracket 111, and a coil 13.
The permanent magnet 15 is ring-shaped, the burring part 18 extends downward from the center of the yoke 141, and the weight body 16 is installed on an outer peripheral surface of the permanent magnet 15. The permanent magnet 15 is disposed coaxially with the coil 13 to form a magnetic circuit together with the yoke 141. A resilient body 17 is installed between the vibrator 14 and the bracket 111 to support the vibrator 14 during an operation of the vibrator 14. A Flexible Printed Circuit Board (FPCB) may be mounted on the bracket 111 and provided to supply electrical connections to the coil.
Since a portable terminal may be frequently dropped by a user while he/she uses the portable terminal employing the linear vibration generating apparatus, an impact generated due to the dropping may cause a central yoke to become separated in the linear vibration generating apparatus. Thereafter, the impact is transferred to a coil, causing the coil to break.
Furthermore, it is difficult to make the central yoke be concentric when the linear vibration generating apparatus is assembled. That is, although the central yoke should be assembled to be accurately concentric with the permanent magnet and the coil during the assembling process, the concentricity of the central yoke, which is made of a metal, may not be achieved due to a magnetic force of the permanent magnet. Accordingly, the assembling efficiency of the linear vibration generating apparatus is lowered, making it difficult to reduce manufacturing costs.
Therefore, a need exists for a linear vibration generating apparatus which can prevent the separation of a coil of a central yoke to prevent the coil from being broken and enhance an assembling efficiency related to a process of aligning the concentricity of the central yoke.